Steel Fibre Self-compacting Concrete Research Articles

Regression Anaylsis for the Experimental Study on the Pullout Strength of Steel Fiber Self- Compacting Concrete

This article describes experimental research of the interfacial adhesion of triple blended steel fibre self-compacting concrete (TBSFSCC) and it varies depending on the percentage of steel fibre. In self-compacting concrete, mineral admixtures such as condensed silica fume and flyash are utilised as supplementary cementitious materials (SCMs).the percentage of replacement of cement by condensed silica fume at 10 where as flyash at 20 respectively, to meet the SCC criteria stipulated by ACI. The embedment length of a steel bar with a diameter of 12mm was chosen to be 100mm in all of the standard specimens. Fe-415 steel rod is used in this research. The pull-out test in the universal testing machine is used to evaluate the bond strength of this triple blended Self-Compacting Concrete (TBSCC). Ordinary steel fibres are then added to the concrete volume at various percentages, such as 0.2, 0.4, 0.6, and 0.8. The bond strength, slip, and the method of failure of each rebar were all noted in the test results. The comparison of these results clearly shows that the percentage of steel fibre contributes to the TBSCC bond strength, and conclusions are generated.

Study on static and dynamic mechanical properties of steel fiber self-compacting concrete after heating in a high-temperature

While supporting impact loads, steel fiber self-compacting concrete (SFRSC) is frequently impacted by temperature loads. Therefore, it is essential to investigate how the SFRSC responds mechanically when impact and high temperature are combined. To ascertain the effects of temperature and impact load on the static and dynamic mechanical characteristics of SFRSC, static and dynamic mechanical tests were performed on SFRSC treated at 25 °C, 100 °C, 200 °C, 400 °C, 600 °C, 800 °C, and 1000 °C using the RMT-150C system and SHPB, respectively. The laws of mechanical response changes were presented from the viewpoints of the stress-strain relationship, compressive strength, DCF, DSF, elastic modulus, XRD phase analysis, and failure morphology. Systematically examined were the effects of temperature on mechanical behavior when impact and high temperature are coupled, including the temperature strengthening effect, temperature weakening effect, critical temperature, and strain rate effect. A damage-type viscoelastic constitutive model taking temperature into account was created by incorporating the temperature effect coefficient K and the damage factor D. According to the results, static and dynamic mechanical characteristics were improved at temperatures of 100 and 200 °C, but they dramatically degraded at 400–1000 °C, and strain rate sensitivity significantly increased with temperature.

Performance Evaluation of Hybrid Fibre Reinforced High Volume Fly Ash based Self Compacting Concrete

Self-compacting concrete has become increasingly popular lately for usage in crowded concrete-reinforced buildings having challenging casting circumstances. New cement needs to have high fluidity and strong cohesion for these applications. The necessary concrete characteristics can be ensured through the use of fine elements like fly ash. The preliminary findings of a trial to produce and assess SCC created using large amounts of Fly ash is given and discussed. During this investigation, few SCC combinations and a control concrete is examined. The water/cementitious material ratio is ranges from 0.35 while cementitious material amount remained constant (300 kg/m3). Its self-compacting mixes replaced 25%,35%,37.5%,40%, and 50%, of the cement with fly ash. All mixes were put through tests to determine their viscosity and stability as fresh concrete. Additionally, the compressive strength, Flow Ability Test, Flexural strength and Split Tensile Strength of cured concretes were measured. For the purpose of testing the flow characteristics and mechanical properties of Hybrid Propylene Steel Fibre Self-Compacting Concrete (HPSscc), Steel Fibre in combination with Poly Propylene PP Fibre (Hybrid Fibre) are used to regulate SCC at concentrations of 0.25+0.15%, 0.50+0.30%, 0.75+0.45%, 1.0% + 0.60%, and 1.25+0.75%.The ideal quantity of hybrid fibre is established. The 28-day compressive strengths of the SCCs ranged from 35 to 54 MPa. It is important to research the effects of adding steel fibres to control SCC of various types, aspect ratios, and volume fractions. Concrete can benefit from having its tensile strength increased by using synthetic fibres like polypropylene PP. It is important to achieve the ideal quantity of PP fibres to be added for a specific characteristic of the mix's constituents. Hybrid fibre is used in concrete when more than one fibre is included. The performance of concrete can be improved by using the characteristics of one type of fibre with another type of fibre. Also Flow Ability Test carried out immediately after producing concrete earlier and Split Tensile Strength tests are conducted. The outcomes demonstrate that a cost-effective SCC might be successfully constructed by adding significant amounts(35%) of fly ash.

Regression Analysis for the Bond Strength of Steel Fibre Self-compacting Concrete Based on the Experimental Studies

This article describes experimental research of the interfacial adhesion of triple blended steel fibred self-compacting concrete (TBSFSCC) and it varies depending on the percentage of steel fiber. In self-compacting concrete, mineral admixtures such as condensed silica fume and fly ash are utilized as supplementary cementitious materials (SCMs). Condensed silica fume can replace 10 percent of the cement and fly ash can replace 20 percent of the cement to fulfill ACI's SCC guidelines. The embedment length of a steel bar with a diameter of 12mm was chosen to be 100mm in all the standard specimens. Fe-415 steel rod is used in this research. The pull-out test in the universal testing machine is used to evaluate the bond strength of this triple blended Self-Compacting Concrete (TBSCC). Ordinary steel fibers are then added to the concrete volume at various percentages, such as 0.2, 0.4, 0.6, and 0.8. The bond strength, slip, and the method of failure of each rebar were all noted in the test results. The comparison of these results clearly shows that the percentage of steel fiber contributes to the TBSCC bond strength, and conclusions are generated.

Performance of hybrid glass/steel fibre self-compacting concrete beams under static flexural loading

In this paper, it is proposed to study the static flexural performance of hybrid (glass and steel) fiber reinforced M30 grade self-compacting concrete (SCC) beams made with glass fiber reinforcement polymer (GFRP) re-bars. Nan Su mix design approach is adopted to develop the M30 grade plain SCC (PSCC) mixes. Glass fibre SCC (GFRSCC), steel fibre SCC (GFRSCC) and hybrid fibre SCC (HFRSCC) mixes are prepared using the optimum dosages of glass (0.05%) and steel fibres (1%) by volume fraction. HFRSCC reinforced beams of size 1200 *200*150 mm will be casted with steel and GFRB rebars and tested to study the flexural properties such as ultimate flexural strength, load at first crack, deflection at the center, crack width and crack patterns. For the above fibred beams, load-deflection relations will be established. The HFRSCC beam made with GFRP rebars have the load carrying capacity 37.03% more than HFRSCC beam made with steel rebars. The deflection for the HFRSCC beam made with GFRP rebars is 61.52% more than beam made with steel rebar HFRSCC beam made with GFRP rebars increases the load at first crack, ultimate flexural strength, and deflection at the centre at failure and the crack width for same HFRSCC beam made with steel rebars

Creep Strain Behaviour of Triple-Blended Steel Fiber Self-Compacting Concrete

The objective of the research article is to present the experimental results on the creep strain behaviour of steel fiber Self-Compacting Concrete (SFSCC). In respect of binder content, aggregate size, fine-to-coarse aggregate ratio, water-to-cement ratio, and chemical admixtures, Self-Compacting Concrete (SCC) differentiates from conventional cement concrete. Steel fibers are also inserted into SCC at a predetermined percentage to reinforce it. Steel fibers have been shown to contribute to improved strength characteristics, a dense mass of concrete with little or no voids, reduced pores in concrete, a higher Young’s modulus, and fewer deflections and strains in concrete. Hence, an investigation was conducted on the creep variation of SFSCC over a longer duration. The test approach follows ASTM C512’s standard test method for concrete creep in compression. The test specimens (SFSCC) are standard cylinders that have been cast and cured for 28 days before being tested. Three SFSCC cylinders with 0.80% steel fiber were tested at the same time. The load is applied to just the cylinders in the loading frame and kept constant, producing constant stress. The strains that occur only due to creep, excluding the initial elastic strain, are digitally recorded. As a logarithmic function, the creep strain-time connection was established. The conclusions are observed based on the findings of the experiments and compared with normal cement concrete (NCC).

Shear capacity of precast half-joint beams with steel fibre reinforced self-compacting concrete

A complex geometry of precast reinforced concrete half-joint beams has resulted from the high shear force at the recessed ends of such beams. Immense levels of reinforcements are provided close to the re-entrant corner of these beams to prevent the propagation of diagonal cracks and sudden failure. However, this condition leads to reinforcement congestion and affects the bond between concrete and reinforcing steel due to improper concrete filling around the congested bars. Hence, the use of steel fibre self-compacting concrete (SFRSCC) was found to combine the advantages of eliminating the vibration works, and reduction of secondary reinforcement. An experimental study was conducted to examine the ability of 1.0% by volume of steel fibre to partially replace the traditional reinforcements on two types of half-joint beams (short recess (SR) and deep recess (DR) beams). Other factors taken into account is the variance in shear span values and nib height, as well as the ratio of shear-span-to-depth, av/d. Observations showed that the replacement of 1.0% by volume of steel fibre volume fraction is possible only when substituting at least 50% of the vertical or horizontal reinforcement in SR beams. Meanwhile, the replacement over diagonal reinforcement is seemed to be not enough and the replacement is only promising in substituting part of stirrups in DR beams. The variance in the shear-span-to-depth av/d ratio affects the shear failure mode of the beam half-joints. Two semi-empirical equations for predicting the shear strength of precast SCC and SFSCC beam-half joints are developed based on the analysis of failure modes. The first equation, which relies on the crushing of the concrete strut, was found to suit the SR beams, while the equation for DR beams suits the theoretical of reinforcement yielding. The two equations give a good correlation with the experimental results.

Research of Shear Experiment of Interface between New Steel Fiber Self-compacting Concrete and Old Ordinary Concrete

In prefabricated concrete structure, the shear performance of interfaces between prefabricated parts and cast-in-place parts needs improvement. Steel fiber self-compacting concrete is a desirable kind of concrete to solve this problem. This paper introduced Z-shape specimens with interfaces between new steel fiber self-compacting concrete part and old ordinary concrete part as direct shear experiment objects. Factors including steel fibers volume ratio and inserting rebars were also studied. The results show that the shear strengths of interfaces increase with the increases of steel fibers volume ratio, and inserting rebars can improve shear strengths and change failure form from brittle failure to ductile failure.

The fibre shear supplement of precast beam-half joints using steel fibre self-compacting concrete

The end region of the dapped-end beam experienced multiaxial stress actions, which requires high amounts of reinforcement and this resulted to the closely space reinforcement. Therefore, hooked-end steel fibres were mixed into all beam specimens to partly replace the secondary shear and bursting reinforcement to reduce the congestion issue. A series of experiments were performed on shallow recess (SR) and deep recess (DR) half joint beams to examine the partial reduction of reinforcement with 1% replacement of steel fibre. All SR and DR beams were then tested under shear load to study the effectiveness of steel fibres over traditional reinforcement in resisting loads, with two different shear span-to-depth ratios, which are 1.4 and 2.1. The experimental shear strength fibre supplement results for the SR and DR beam specimens were compared with theoretical predictions using the analytical and RILEM methods. The incorporation of 1% of steel fibre in the concrete matrix has the ability to replace 50% of horizontal and vertical reinforcement in SR and DR beams. In general, it is found that both the analytical and RILEM methods give a close approximation for the experimental DR beam specimen values, but slightly overestimated the fibre shear supplement of SR beam specimens by 13.4%. The results support the ability of steel fibres to resist tensile stress through its fibre-bridging action.

Properties of steel fiber self-compacting concrete incorporating quarry dust fine powder

Self-compacting concrete (SCC) has great potentials as it offers several environmental, economic and technical benefits. Moreover, the use of fibers extends its possibilities since fibers arrest cracks and retard their propagation. Incorporation of Quarry Dust (QD) in SCC help to reduce environmental hazards during the production of QD. This study evaluated the fresh and hardened properties of steel fiber self-compacting concrete (SFSCC) incorporating QD. The optimum fiber and QD contents with no adverse effects on fresh and hardened properties were determined. A comparative study on behavior of SCC and SFSCC mixtures in terms of workability, compressive strength, compressive strength development ratio, tensile, flexural and energy absorption capacity was carried out. Test results showed that compressive strength increased with increase in QD contents at fixed fiber content by mass of Portland cement (PC) and then decreased. Strength development ratio (C28/C7) for SCC was 1.13, while it was 1.06, 1.08, 1.10 and 1.01 after reinforcing with 0.10, 0.20 and 0.30 contents of fiber. The compressive, tensile, flexural and energy absorption capacity or Toughness of SFSCC increased with the inclusion of the aforementioned contents of steel fiber up to 0.20 % volume of total binder at constant QD content and then decreased when compared with control SCC values. From these results, optimum value for the variables studied was obtained from mix QD20 + 0.2fr. Hence, steel fiber and QD could be successfully used in SCC production not minding the slight draw back on workability of SCC caused by inclusion of steel fiber, but with a modified dosage of super-plasticizer (SP), fresh and hardened properties, in accordance with specifications in relevant code(s) can be achieved.

Steel fibre self-compacting concrete under biaxial loading

This study involves the investigation of the effects of steel fibre content volume on the biaxial stress behaviour of steel fibre self-compacting concrete (SFSCC) at different stress ratios. This study covers compression-compression, compression-tension, and tension-tension stress regions. The results are discussed in terms of the uniaxial and biaxial strength, stress-strain relationship, and failure mode of SFSCC specimens. In terms of strength, 1.0% fibre volume fractions showed the highest increment in biaxial compression and compression-tension, which were 55% and 84%, respectively, when compared to plain concrete. This improvement was due to the integration of steel fibre. In contrast with compression strength, biaxial tension strength decreased in comparison to uniaxial tensile strength. Additionally, based on the octahedral stress space, the failure criteria of concrete for each region were proposed in a quadratic polynomial equation, and the parameters were derived from a regression analysis.

Preliminary Investigation on the Flexural Behaviour of Steel Fibre Reinforced Self-Compacting Concrete Ribbed Slab

A ribbed slab structure has the advantage in the reduction of concrete volume in between the ribs resulting in a lower structural self-weight. In order to overcome the drawbacks in the construction process, the application of steel fibre self-compacting concrete (SCFRC) is seen as an alternative material to be used in the slab. This preliminary investigation was carried out to investigate the flexural behaviour of steel fibre selfcompacting concrete (SCFRC) as the main material in ribbed slab omitting the conventional reinforcements. Two samples of ribbed slab were prepared for this preliminary study; 2-ribbed and 3-ribbed in 1 m width to identify the effect of the geometry to the slab’s flexural behaviour. The dimension of both samples is 2.5 m x 1 m with 150 mm thickness. The compressive strength of the mix is 48.6 MPa based on the cubes tested at 28 days. Load was applied to failure by using the four point bending test set-up with simple support condition. The result of the experiment recorded ultimate load carrying capacity at 30.68 kN for the 2-ribbed slab and 25.52 kN for 3-ribbed slab. From the results, the ultimate load of the 2-ribbed sample exceeds 3-ribbed by approximately 20%. This proved that even with lower concrete volume, the sample can still withstand an almost similar ultimate load. Cracks was also observed and recorded with the maximum crack width of 2 mm. It can be concluded that the steel fibres do have the potential to withstand flexural loadings. Steel fibre reduces macro-crack forming into micro-cracks and improves concrete ductility, as well as improvement in deflection. This shows that steel fibre reinforced self-compacting concrete is practical as it offers good concrete properties as well as it can be mixed, placed easier without compaction.

Preliminary investigation on the flexural behaviour of steel fibre reinforced self-compacting concrete ribbed slab

A ribbed slab structure has the advantage in the reduction of concrete volume in between the ribs resulting in a lower structural self-weight. In order to overcome the drawbacks in the construction process, the application of steel fibre self-compacting concrete (SCFRC) is seen as an alternative material to be used in the slab. This preliminary investigation was carried out to investigate the flexural behaviour of steel fibre selfcompacting concrete (SCFRC) as the main material in ribbed slab omitting the conventional reinforcements. Two samples of ribbed slab were prepared for this preliminary study; 2-ribbed and 3-ribbed in 1 m width to identify the effect of the geometry to the slab’s flexural behaviour. The dimension of both samples is 2.5 m x 1 m with 150 mm thickness. The compressive strength of the mix is 48.6 MPa based on the cubes tested at 28 days. Load was applied to failure by using the four point bending test set-up with simple support condition. The result of the experiment recorded ultimate load carrying capacity at 30.68 kN for the 2-ribbed slab and 25.52 kN for 3 ribbed slab. From the results, the ultimate load of the 2-ribbed sample exceeds 3-ribbed by approximately 20%. This proved that even with lower concrete volume, the sample can still withstand an almost similar ultimate load. Cracks was also observed and recorded with the maximum crack width of 2 mm. It can be concluded that the steel fibres do have the potential to withstand flexural loadings. Steel fibre reduces macro crack forming into micro-cracks and improves concrete ductility, as well as improvement in deflection. This shows that steel fibre reinforced self-compacting concrete is practical as it offers good concrete properties as well as it can be mixed, placed easier without compaction.

Preliminary Investigation on the Flexural Behaviour of Steel Fibre Reinforced Self-Compacting Concrete Ribbed Slab

A ribbed slab structure has the advantage in the reduction of concrete volume in between the ribs resulting in a lower structural self-weight. In order to overcome the drawbacks in the construction process, the application of steel fibre self-compacting concrete (SCFRC) is seen as an alternative material to be used in the slab. This preliminary investigation was carried out to investigate the flexural behaviour of steel fibre self-compacting concrete (SCFRC) as the main material in ribbed slab omitting the conventional reinforcements. Two samples of ribbed slab were prepared for this preliminary study; 2-ribbed and 3-ribbed in 1 m width to identify the effect of the geometry to the slab’s flexural behaviour. The dimension of both samples is 2.5 m x 1 m with 150 mm thickness. The compressive strength of the mix is 48.6 MPa based on the cubes tested at 28 days. Load was applied to failure by using the four point bending test set-up with simple support condition. The result of the experiment recorded ultimate load carrying capacity at 30.68 kN for the 2-ribbed slab and 25.52 kN for 3-ribbed slab. From the results, the ultimate load of the 2-ribbed sample exceeds 3-ribbed by approximately 20%. This proved that even with lower concrete volume, the sample can still withstand an almost similar ultimate load. Cracks was also observed and recorded with the maximum crack width of 2 mm. It can be concluded that the steel fibres do have the potential to withstand flexural loadings. Steel fibre reduces macro-crack forming into micro-cracks and improves concrete ductility, as well as improvement in deflection. This shows that steel fibre reinforced self-compacting concrete is practical as it offers good concrete properties as well as it can be mixed, placed easier without compaction.

Structural behaviour and fracture energy of recycled steel fibre self-compacting reinforced concrete beams

Mechanical strength and structural behaviour of Recycled Steel Fibre Self-Compacting Concrete (RSFSCC) were investigated using different Recycled Steel Fibre (RSF) contents (30, 45 and 60 kg/m3) incorporated in three SCC mixes. The corresponding steel fibre volume fraction can be approximated to (0.4%, 0.6% and 0.8%) of the concrete mixtures, respectively. Compressive, splitting, and flexural strengths in addition to water absorption tests were performed to investigate some hardened properties of the tested mixes. The structural behaviour was assessed by determining and calculating flexural stiffness k, flexural toughness I and residual strength factor R for reinforced concrete beams having the dimensions of 100 × 150 × 1000 mm. Fractal dimension D was calculated using Image Processing Technique for all assessed beams to study and quantify the cracks and their tortuosity. It was found that incorporating RSF improved the mechanical properties, strength and structural behaviour of SCC. However, the best strength and behaviour in addition to best cracking resistance were achieved using 60 kg/m3 RSF content. Both first crack and ultimate load capacity were increased with RSF incorporation. The flexural stiffness and toughness in addition to residual strength factor increased with incorporating RSF. In addition, fracture mechanics parameters are determined and discussed.

Flexural behavior of self-compacting concrete beams strengthened with steel fiber reinforcement

Steel fiber self-compacting concrete (SFSCC) is an innovative material that can flow underneath its own weight in the fresh state, thus eliminating any need for mechanical vibration and complexity of the formwork, and which employs the benefits of steel fiber addition in the hardened state. Hence, this study evaluated the performance of a self-compacting concrete (SCC) under the effect of filler addition and then investigated the effect of steel fiber (SF) addition on flexural behavior, splitting tensile strength, compressive strength, and modulus of elasticity. Fourteen reinforced concrete beams were tested under monotonic loads: two sets of six SCCs (with and without SFs) and two normal concretes (NCs). Ultimate capacity, deflection, crack pattern, and mode of failure were recorded. The present experimental and theoretical results were compared in accordance with ACI 318 codes to assess the applicability of the aforementioned methods to predict the flexural strength of SCC specimens. The results of the tests carried out on fresh concretes indicate excellent deformability without blocking. Moreover, the flexural strength in beams increases with increasing concrete compressive strength, longitudinal steel reinforcement ratio, and SF amount.

EXPERIMENTAL RESULTS ON THE SHEAR BEHAVIOUR OF STEEL FIBRE SELF-COMPACTING CONCRETE (SFSCC) BEAMS

This paper presents an experimental test program that was carried out to investigate the shear performance of steel fibre self-compacting concrete (SFSCC) beams. In this paper, the mechanical performance of results from all mixtures used to cast normal concrete (NC), self-compacting concrete (SCC) and steel fibre self-compacting concrete (SFSCC) were also investigated. In total, 27 cubes, 9 cylinders, 9 prisms and 9 beams were prepared for the assessment of mechanical properties of three different mixtures. Four beams (125 mm x 250 mm x 2200 mm) were tested and cast using three different concrete mixtures, having two different spacing of stirrups as a result of 50% reduction of the stirrups amount. Three beams with different mixtures having similar stirrups spacing 125mm while the fourth beam with SFSCC mixes having 250mm stirrups spacing. The results show that the mechanical properties were positively affected with steel fibres inclusion. The addition of steel fibres showed an increment up to 40% in the shear load capacity for B-SFSCC125 compared to B-NC125 and B-SCC125. In addition, the crack pattern of B-SFSCC was found better than B-NC and B-SCC.

Frost durability of steel fiber self-compacting concrete for pavements

The paper presents the results from the research on self-compacting concrete with different steel fibre type addition. The reference self-compacting concrete mix with water/binder = 0.33 was prepared, then modified with steel fibres in the amounts of 0–60 kg/m3 and air entrained with polymer microspheres (40 μm diameter). The major objective of the research was to determine the effect of steel fibre and air content on the self-compacting concrete mix properties and hardened concrete frost durability. The tests also included internal cracking and scaling resistance evaluation for concrete specimens subjected to cyclic freeze-thaw process − two beams were frozen in air and two beams were partially submerged in water and then frozen. The scaling resistance was tested using the slab method on the specimens with sawn surface and on the specimens with natural finished surface. Non-air entrained steel fibrereinforced concretes, despite their high strength class (C55/67–C60/75) and medium absorption (4.34–5.11%), showed unsatisfactory resistance to internal cracking and scaling tests. The beams partially submerged in water failed after 100 freeze-thaw cycles, which confirms a significant influence of water uptake from moist environment during freeze-thaw cycles and the acceleration of the damage process. Test results indicate that air entrainment with polymer microspheres is a very effective method and allows obtaining very good air pore structure parameters and frost resistance results. The specimens with top − finished surface exhibited less damage in the scaling resistance tests in relation to the specimens with sawn surface.

Research of Steel Fiber Self-Compacting Concrete Frost Resistance

With the fast freeze-thaw test method, the c50 steel fiber self-compacting concrete was carried out 300 tests of freeze-thaw cycle. In the process of freeze-thaw cycles, it determined by the quality of the concrete specimen, dynamic elastic modulus and strength, and analyzed the steel fibers and their different contents on frost resistance of self-compacting concrete impact. The results showed that: steel fiber self-compacting concrete in freeze-thaw cycle can play constrained role in the quality loss, dynamic elastic modulus and intensity, and can significantly improve the self-compacting concrete frost resistance. Within a certain range, the more steel fiber, the stronger of frost resistance.